Tom Sherbourne is a war hero who is haunted by what he witnessed and what he had to do to survive the trials of World War I. As Tom recovers from his experiences, he clings to his sense of right and wrong in his attempt to navigate life after the war. He is a quiet man who lost his mother as a young boy and became estranged from his brother and overly strict father.

Tom finds comfort in the solitude and simplicity offered by life on Janus Rock, where his time is clearly ordered by the rules and duties of being the lighthouse keeper. He respects the power of nature and finds comfort in the fact that, eventually, his life will be a meaningless blip in the timeline of the universe.

He is deeply surprised when he falls in love with Izzy, and for the first time, he allows himself hope for a happy future. He struggles deeply when his moral code conflicts with the happiness of his wife. In raising Lucy, the baby who washes up on the shore of Janus Rock, he discovers a tenderness of which he never knew he was capable.